1. Field of the Invention
The present disclosure relates generally to catheter devices and methods for protecting against embolic debris during vascular interventions. More particularly, the devices and methods described herein can be used with endovascular procedures in a mammalian body and achieve blood flow-reversal within the arterial vasculature as well as blood return without a venous return.
2. Discussion of the Related Art
Contralateral flow occurs when there are arterial vessels that are in fluid communication at two points, e.g. a proximal and distal location. When the fluid pressure in one arterial conduit drops, the pressure from the other arterial conduit can cause the blood from the other side to flow into this conduit. For example, the arterial side of the cerebral circulatory system generally can be seen as divided into two sets of contralateral arteries, both sets originating from the aortic arch with one set feeding the left side of the brain and the other set feeding the right side. A large number of minor and major communicating vessels connect these contralateral arteries. As such, if the blood pressure becomes low enough on a given side, the pressure on the contralateral is sufficient to cause blood to flow across the communicating vessels and in a retrograde fashion towards the low-pressure source. Artificially and temporarily occluding the natural antegrade flow in a cerebral vessel and providing a low-pressure outlet for the blood can induce this retrograde effect.
This effect can be particularly useful when treating an artery in or near the cerebral vasculature, or in another vessel with similar contralateral flow properties. Endovascular treatment of a blood vessel, which has a reduced diameter, for example, through the effects of lesions called atheroma or the occurrence of cancerous tumors, can generate free-floating debris. Such debris may cause damaging embolisms, and embolisms occurring in the brain are particularly dangerous. By inducing retrograde flow across a lesion in a cerebral vessel, any debris generated can be routed away from the brain.
Current devices that create reverse flow may be improved upon in a variety of respects. For example, some devices require withdrawal of the patient's blood to create retrograde flow across a lesion, and the patient's blood during this process is not conserved. Furthermore, current devices may not maintain continuous reverse flow but rather intermittent reverse flow. Maintaining a continuous reverse flow rather than an intermittent reverse flow further minimizes the risk that embolic debris will migrate toward the brain. Another current device does conserve blood and does maintain constant flow. However, this device requires multiple access sites within a patient's vasculature, which presents more risk to the patient and impacts ease of use for the clinician. Therefore, there is a need for endovascular devices and methods that create reverse flow and protect against embolic debris while conserving the patient's blood and requiring only a single vascular access site.